I think you're right about it being a Samsung thing, part of the error is that it can't communicate with the network, yet we have full APN access. I called AT&T about it, they said other people are calling as well but so far do not have a solution. I'm going to try replacing the default email.apk with one that has less security, see if that makes a difference.
Edit: it didn't make any difference. I also tried Samsung's online support, that turned out to be totally useless. As much as I really don't want to do it, I'm going to go with CM7 until we figure this out.